Apparatus and method for controlling a locomotive consist

ABSTRACT

A locomotive assembly including a legacy locomotive controller and an intercept locomotive controller and a method of controlling a locomotive are disclosed. The locomotive assembly includes a locomotive having a power bus, a primary power unit coupled to the power bus, and a legacy locomotive controller programmed to transmit control signals to the primary power unit. The locomotive assembly further includes an intercept locomotive controller programmed to receive a control signal indicating an requested amount of locomotive power from the legacy locomotive controller, allocate a portion of the requested amount of locomotive power to an auxiliary power unit, and control the auxiliary power unit to deliver the portion of the amount of locomotive power to the power bus.

CROSS REFERENCE TO RELATED APPLICATION

The present invention is a continuation of and claims priority to U.S.Provisional Patent Application Ser. No. 61/799,474, filed Mar. 15, 2013,the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

A locomotive consist is the arrangement of locomotives, slugs, and powertenders which are coupled together to provide motive power to a train.In one known arrangement, multiple independent locomotives are linkedtogether using multiple-unit (“MU”) controls and operated as a singleunit. Locomotives traditionally used in MU arrangements are powered bydiesel-electric power sources, where a diesel engine drives a generatorto produce electric power. The electricity produced by theseengine-generator sets is in turn used to power one or more electrictraction motors. The traction motors turn the drive wheels of thelocomotive.

The locomotive controllers provided on traditional locomotives, referredto herein as “legacy locomotive controllers”, recognize and controlfixed engine-generator combination(s) installed on the locomotivechassis. This arrangement of locomotives has an independent legacylocomotive controller for each locomotive chassis, and shares throttlesetting (an input to a locomotive controller), brake settings, and faultindications, which are communicated using a combination electrical andpneumatic connection. Each legacy locomotive controller manages astatic, predefined arrangement of one or more engine/generator sets thatprovide power to the bus, and the generation of tractive effort bytraction motors that use the provided electricity. These locomotivecontrollers also manage fuel use and efficiency, emissions production,and other aspects of the locomotive operation. MU controls relaythrottle and brake instructions from a first locomotive (master or “A”units) to one or more second locomotives (slaves or “B” units), wherethese instructions are independently interpreted by the respectivelocomotive controller and tractive effort is provided independently byeach locomotive of a consist. MU locomotives operate independently anddo not share power or engine control signals, nor do they permit a firstlocomotive controller to make requests of a second locomotivecontroller. Similarly, legacy locomotive controllers of locomotivesoperating in MU fashion do not share operational data and do not makeoperational decisions about the operations of a first locomotivecontroller based upon the operational characteristics of the secondlocomotive controller.

Legacy locomotives comprise those locomotives which do not have alocomotive controller that is able to manage multiple simultaneous powergeneration sources. Legacy locomotives which support multiplesimultaneous power generation sources are called “genset” locomotives,as described above.

FIG. 1 is a block schematic diagram illustrating a typical legacy DClocomotive system 10. The DC locomotive system 10 includes two controlloops: an engine control loop 12 and an electrical-power control loop14. These control loops are implemented by legacy locomotive controller16. A legacy locomotive controller 16 is an analog electro-mechanicalassembly, a digital microcontroller-based control system that implementsthese control loops, or a combination of these technologies. A throttleor “Notch” setting or notch request 18 is set by the operator and is aninput to the legacy locomotive controller 16. In the engine control loop12, the Notch setting 18 is an encoded request for a particularlocomotive power setting and is used by the legacy locomotive controller16 to calculate a set-point for engine speed. The engine control loop12, implemented by the legacy locomotive controller 16, is responsiblefor tracking and managing that speed. The electrical control loop 14 oflegacy locomotive controller 16 uses the Notch setting 18 to determine apower set-point. The legacy locomotive controller 16 then manages theelectrical output power of the engine/generator combination to thatpower set-point. Collectively, these systems are called “legacylocomotive control systems”.

The high-level schematic diagram for a typical AC locomotive is verysimilar to that shown in FIG. 1 with the exception that instead of theDC bus wiring directly to DC motors, the power source for the ACinduction motors is controlled by a separate AC controller. The ACcontroller is responsible for distributing power (and reducing it duringknockdowns). In an AC locomotive, the DC bus voltage is stored oncapacitors which ensure stable power while the AC induction invertersswitch the power to the wheels. Thus, for an AC locomotive, the powercontrol portion is similar to that of a DC locomotive.

Legacy locomotive controllers can be generally characterized asoutputting engine control voltages (e.g., RPM and generator excitementvoltages), receiving sensor input of operational information (e.g.,sensor readings indicating actual engine RPM, some fault information,and, in some cases, power bus sensor readings), and then acting toadjust the operation of the engine by varying its control voltages. Inlocomotives that include multiple engine-generator sets, the legacylocomotive controller manages the locomotives engines and provides powerblending by controlling the amount of power and voltage provided by eachengine to the common power bus, which permits the provided power to becombined on the power bus.

Legacy locomotive controllers are constructed with a basic assumptionthat the power sources that they control are provided in a fixedarrangement. If a legacy locomotive controller is unaware of multiplepossible power sources, then the use of an external power tender canonly be provided on an “all or nothing” basis, where the power tenderdirectly substitutes for the engine-generator on the locomotive chassis.Given the complex nature of locomotive control and the interrelatednessof locomotive loads such as traction motors and blowers, a locomotive'scontroller, its engine-generator, and an external power tender cannot“share” the generation requirement, with a portion of the power comingfrom the engine-generator, and remainder of the power coming from theexternal power tender without the legacy locomotive controller beingaware of the power tender and the amount of power it produces. As justone example, the heat generated by the locomotive's electric tractionmotor must be continuously rejected from the motor apparatus to preventmotor damage and catastrophic failure including fires in the worstcases. In order to reject this heat from the traction motors,locomotives use forced air blower systems to pass air through theinternal structure of each traction motor. The power to turn thetraction motor blowers comes from the locomotive diesel engine in eithermechanical or electrical form. In both instances, the drive speed of themotor blowers is related to the operating speed or power output of thelocomotive and adjusting the locomotive diesel engine to compensate forpower provided from external sources will reduce the cooling of thetraction motors without reducing their actual load (and heatgeneration).

If the legacy locomotive controller is not programmed to be aware of anadditional power source programmed to deliver power to the bus, thelegacy locomotive controller will recognize the additional poweravailable on the locomotives power bus and either fault, mis-control oneor more power sources or loads, or even turn off the locomotive'sengine-generator. In addition, the addition of unexpected auxiliarypower sources may result in improper control of other locomotive systemstied to the locomotive engine-generator or to the amount of power beingused by locomotives loads (e.g., blowers, auxiliary power), therebyresulting in a non-functioning locomotive.

While some legacy locomotive controllers have been configured to controlstatic arrangements of dissimilar power sources (such as anengine-generator, fuel cell, gas turbine, or batteries) in an effort toreduce emissions and fuel costs, extend locomotive limits, and improvethe efficiency of locomotive power, these static arrangements havefailed due to the lack of operational flexibility required forday-to-day operation of locomotives and/or operational limitations (suchas locomotive range, power production limitations, and requiring supportfor multiple fuel sources).

Further, the legacy locomotive controllers of existing diesel enginesare configured with built-in assumptions regarding the power curve andengine settings (e.g., RPM, generator excitement) that are used toproduce specific power/voltages. These operating assumptions areviolated by physical limitations induced by separating the power tenderfrom the locomotive chassis (as described above), and by logicalconsiderations that power tenders may have different operatingparameters and settings (e.g., differing engine type, characteristics,fuels). In current configurations, power tenders and locomotivecontrollers must be operated as a single, non-varying consist because ofinherent limitations in the locomotive control and the lack oflocomotive controller knowledge of differing power tenders and eachpower tenders instructions and operational characteristics. The lack offlexibility of these older control systems prohibits the use of newer,more desirable, power sources capable of operating with alternative fuelsources and limits operational flexibility made available by swappingout of service units (which takes an entire locomotive/power tendercombination out of service).

Newer locomotive power control systems have evolved fromelectro-mechanical to digital controls offering a variety of new optionsfor power control that perform the same functions as the olderelectro-mechanical control systems, as well as add new power managementand train control functions in order to improve performance and fuelefficiency. However, the cost and technical integration challenges ofretrofitting these digital controllers to pre-existing (legacy)locomotives is problematic and are often prohibitive. Generally, thisretrofit requires the wholesale replacement of the locomotive controlsystem and some of the locomotive control circuits, as well assubstantial modifications to the locomotive engine, generator, and otherelectrical components on the locomotive. Furthermore, these types ofchanges typically cause a reclassification of the locomotive and requirerecertification of the locomotive power plant for safety and emissions.The recertification process requires that the engine emissions beupdated to current EPA requirements, which adds additional cost.Combined, these costs are prohibitive.

In light of the above, it would be advantageous to maintain the abilityto operate an existing locomotive engine using the fuel for which it wasoriginally designed while adding the ability provide extra power to thatlocomotive from an auxiliary power source.

It would further be desirable to design an apparatus and method forproviding an auxiliary power source for a locomotive that can beintegrated with existing electro-mechanical locomotive controls toprovide the benefits of being able to incorporate power from alternativefuel sources without replacing or reprogramming the pre-existinglocomotive controller.

It would also be desirable to design an apparatus and method thateffects proper control of locomotive systems tied to the locomotiveengine-generator, such as traction motors and traction blower motors,when an auxiliary power source is used to deliver power to thelocomotive power bus.

BRIEF DESCRIPTION OF THE INVENTION

Embodiments of the invention overcome the aforementioned drawbacks byproviding a method and apparatus for retrofitting a legacy locomotivecontrol system with an intercept locomotive controller to enable the useof situational-appropriate auxiliary power sources and permit railroadlocomotives to make cost-advantaged use of alternative power sourceswhen it is cost effective to do so without reprogramming or replacingthe existing legacy locomotive controller.

Embodiments of the invention relate generally to the management oflocomotives utilizing one or more auxiliary power units and, moreparticularly, to a method and apparatus for equipping an existinglocomotive with an intercept locomotive controller designed to manageauxiliary power sources and interface with the existing legacylocomotive controller of the locomotive.

In accordance with one aspect of the invention, a locomotive assemblyincludes a locomotive having a power bus, a primary power unit coupledto the power bus, and a legacy locomotive controller programmed totransmit control signals to the primary power unit. The locomotiveassembly further includes an intercept locomotive controller programmedto receive a control signal indicating an requested amount of locomotivepower from the legacy locomotive controller, allocate a portion of therequested amount of locomotive power to an auxiliary power unit, andcontrol the auxiliary power unit to deliver the portion of the amount oflocomotive power to the power bus.

In accordance with another aspect of the invention, a method ofcontrolling a locomotive includes relaying a control signal from alegacy locomotive controller to an intercept locomotive controller, thecontrol signal comprising an encoded request for a locomotive powersetting. The method also includes determining a desired power outputcorresponding to the locomotive power setting and allocating a firstportion of the desired power output to an auxiliary power source.Further, the method includes transmitting an auxiliary command signalfrom the intercept locomotive controller to the auxiliary power sourceto cause the auxiliary power source to supply the first portion of thedesired power output to a locomotive bus on the locomotive.

In accordance with yet another aspect of the invention, a retrofit kitfor a locomotive includes a first control interface electricallycoupleable to a legacy locomotive controller on the locomotive. Theretrofit kit also includes an auxiliary power unit assembly having anauxiliary power source, an auxiliary controller programmed to controlthe auxiliary power source, a power cable coupleable to a power bus ofthe locomotive, and a second control interface electrically coupled tothe auxiliary controller. Further, the retrofit kit includes anintercept locomotive controller electrically coupled to the first andsecond control interfaces. The intercept locomotive controller isprogrammed to interpret a signal received on the first control interfaceas a request for locomotive power, define an auxiliary power commandbased on the request for locomotive power, and transmit the auxiliarypower command to the auxiliary power unit assembly via the secondcontrol interface.

These and other advantages and features will be more readily understoodfrom the following detailed description of preferred embodiments of theinvention that is provided in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate preferred embodiments presently contemplated forcarrying out the invention.

In the drawings:

FIG. 1 is a schematic block diagram illustrating a control system of aprior art diesel genset locomotive.

FIG. 2 is a schematic diagram of a locomotive assembly including alegacy locomotive with an intercept locomotive controller and anauxiliary power unit assembly, in accordance with an embodiment of theinvention.

FIG. 3 is a schematic diagram of an exemplary intercept locomotivecontroller usable with the locomotive assembly illustrated in FIG. 2.

FIG. 4 is a schematic block diagram of select components of thelocomotive assembly of FIG. 2, in accordance with an embodiment of theinvention.

FIG. 5 illustrates an exemplary control process for controlling alocomotive assembly, such as the locomotive assembly of FIG. 2, inaccordance with an embodiment of the invention.

DETAILED DESCRIPTION

Embodiments of the invention disclosed herein include an “intercept”locomotive controller integrated within the existing control circuitryof the control system of a legacy locomotive, such as legacy locomotive10 of FIG. 1. As described in detail below, the intercept locomotivecontroller receives control and sensor inputs from a variety of sources,including one or more pre-existing locomotive controller outputs, suchas, for example Notch settings, and provides sensor or other outputs topre-existing locomotive controller inputs and locomotive power or otherlocomotive equipment. Using the output signals received from the legacycontroller, the intercept locomotive controller recalculates the powerallocation between the legacy locomotive engines and to one or moreauxiliary power units and transmits differing signals to the legacylocomotive engines and to one or more auxiliary power units. Theintercept locomotive controller also receives signals from sensors onthe locomotive and sensors located on one or more auxiliary power unit(APU) assemblies coupled to the locomotive and synthesizes those signalsinto signals expected by the legacy locomotive controller.

Because the intercept locomotive controller is configured to interceptboth signals output from the legacy locomotive controller and signalsinput to the legacy locomotive controller, such as sensor inputs forexample, the intercept locomotive controller can interoperate with theexisting legacy locomotive controller without making modifications tothe existing legacy locomotive controller or replacing the legacylocomotive controller with a “genset” style locomotive controller thathas been modified to interoperate with one or more removable auxiliarypower units. Therefore, this “intercept” controller architecture has theadvantage of enabling legacy locomotives to interface with auxiliarypower units and operate with lower costs and with reduced emissions, andwithout incurring large retrofit expenses or recertification costs.Also, when auxiliary power is not available, the intercept locomotivecontroller can pass the signals through directly without modification totheir legacy destination and the legacy locomotive will work in itsoriginal factory mode.

Referring now to FIG. 2, a locomotive consist or locomotive assembly 110that includes an intercept locomotive controller 162 is illustratedaccording to one embodiment of the invention. As shown, locomotiveassembly 110 includes a locomotive 112 that is coupled to auxiliarypower unit assembly 48 via power and control cables 100, 142. Alocomotive consist is defined for purposes herein as an arrangement oflocomotives and auxiliary power units, coupled together, which sharecontrol and power connections between at least one locomotive and atleast one auxiliary power unit. For purposes of illustration, severalexemplary configurations of consists may be defined as follows:

A-B Consist: One locomotive coupled to one auxiliary power unit. Theauxiliary power unit provides at least some, but not all, of theelectrical power required by the locomotive.

A-B-A Consist: Multiple locomotives are coupled to one auxiliary powerunit. The auxiliary power unit provides a least some, but not all, ofthe electrical power required by each of the locomotives.

A-B-B Consist: One locomotive is coupled to multiple auxiliary powerunits. The auxiliary power units together provide at least some of theelectrical power required by the locomotive.

Referring first to the locomotive portion of the locomotive assembly 110of FIG. 2, locomotive 112 includes a locomotive control system 113having a legacy locomotive controller 114 and an intercept locomotivecontroller 162. Similar to legacy locomotive controller 16 (FIG. 1),legacy locomotive controller 114 is configured to manage a pre-definedarrangement of one or more fixed locomotive engine-generator sets 116designed to operate in response to received control signals from legacylocomotive controller 114. Such predefined and static operatingarrangements may be stored within legacy locomotive memory 115. Thenumber of engines/generator sets 116 included within locomotive 112 andthe associated control inputs and outputs are simplified for clarity inthis illustration. As such, while locomotive 112 is illustrated asincluding a single locomotive engine-generator set 116, locomotive 112may include additional fixed power sources according to variousembodiments. The legacy locomotive controller 114 provides a pluralityof control inputs and outputs between the legacy locomotive controller114, the engine/generator set 116, and various sensors 122, 140 thatmonitor the operation of the engine/generator set 116, the traction bus124, and fraction motors 128, as described in additional detail below.

Locomotive engine-generator set 116 includes a respective diesel engine118, generator 120, and sensor system 122. While element 120 isdescribed as a generator herein, alternators may be substituted forgenerators in the power generation system as understood by those skilledin the art. Generator 120 produces electricity for delivery to a DClocomotive fraction bus 124 and an auxiliary power bus 126. According toone embodiment, generator 120 is excited through a silicon controlledrectifier (SCR) 121 (shown in phantom). In an alternative embodiment,generator 120 is excited using a pulse-width-modulated (PWM) signal.Generator 120 is configured to convert the mechanical energy provided byengines 118 into a form acceptable to one or more traction motors 128(DC or AC type) configured to drive the plurality of axles coupled tothe driving wheels 130 of locomotive 112, and to provide DC or AC powerto the respective auxiliary power bus 126. According to one embodiment,traction motors 128 are cooled via a traction motor blower 204 (FIG. 4),which may be coupled to a power take off of diesel engine 118 or poweredby electrical power derived from diesel engine 118, according to variousembodiments.

In traditional legacy locomotive engine configurations, locomotiveengine-generator set 116 is operated in response to a throttle positioninput sensor 134 which indicates the position of the throttle ascontrolled by the operator on an operator interface 136. Operatorinterface 136 may also include an optional operator engine start input138 (shown in phantom) where the operator can directly or indirectlyinstruct legacy locomotive controller 114 (e.g., via a keypad (notshown)) with regard to operation of engines 118 or termination ofoperation of the engines 118.

The intercept locomotive controller 162 is positioned between theequipment control inputs of legacy locomotive controller 114 and itslocomotive subsystems (e.g., engines, generators, sensors, tractionmotor controllers, collectively referred to herein as “locomotiveequipment”) through one or more interfaces. The intercept locomotivecontroller 162 receives equipment control inputs originally directed tothe legacy locomotive controller 114 or other locomotive equipment andoutputs synthesized values to the respective legacy locomotivecontroller 114 and locomotive equipment to effect the control ofintegrated locomotive equipment and APUs 50. These control inputsinclude information transmitted from user interface 136 to legacylocomotive controller 114 and information transmitted to legacylocomotive controller 114 from power sensors 140 and locomotiveengine/generator sensors 122 that provide information in the form ofanalog electromagnetic signals and/or digital signals, which are read by(and converted to appropriate form by) the intercept locomotivecontroller 162. According to various embodiments, intercept locomotivecontroller 162 includes circuitry to convert the digital and analogsignals to/from a form usable by the intercept locomotive controller162. As one skilled in the art will recognize, this “intercept” paradigmmay be extended to the control of any locomotive equipment as well as tothe control of external locomotives (using an MU interface). The variousinput and output interfaces of intercept locomotive controller 162 areillustrated and described in more detail with respect to FIGS. 3 and 4.

Power sensors 140 on the locomotive traction bus 124 and auxiliary powerbus 126 coupled to intercept locomotive controller 162 through controland sensor circuits provide information on the amount of power actuallybeing provided on the busses 124, 126 and/or to traction motors 128.These sensors are well known by those skilled in the art and may providedigital, analog, or a combination of digital and analog outputs tointercept locomotive controller 162.

Locomotive 112 also includes an engine start and stop control 132 whichinterfaces with legacy locomotive controller 114. In some embodiments,the engine start and stop control 132 is also connected to the interceptlocomotive controller 162 and the intercept locomotive controller 162provides a synthesized engine start and stop control input to the legacylocomotive controller 114, as described in more detail below withrespect to FIG. 4.

As shown in FIG. 2, locomotive 112 is connected to an auxiliary powerunit assembly 48, which includes an auxiliary power unit (APU) 50 thatis designed to interface with one or more locomotives, such as a diesellocomotive and one or more interchangeable gaseous fuel assemblies 52.As used herein, “gaseous fuel” means fuels in liquid or gaseous state(depending upon current temperature and pressure), where the fuel isnormally in a gaseous state at standard temperature and pressure. Inmany cases, these fuels are hydrocarbons such as natural gas, propane,or syngas. Gaseous fuel may also be, for example, compressed orliquefied hydrogen, producer gas, methane, butane, and the like. In theembodiment shown, auxiliary power unit assembly 48 includes one or morefuel assemblies 52 stacked atop the container 54 housing APU 50, whichis secured to a rail car 56. However, one skilled in the art willrecognize that fuel assemblies 52 and APU 50 may be arranged in otherconfigurations in alternative embodiments. As described in detail below,APU 50 provides additional power to the connected locomotive(s) 112 inthe locomotive consist 110 under direction of at least one interceptlocomotive controller 162. As used herein, the term “auxiliary powerunit” or “APU” is used to refer to an autonomously controlled devicecapable of generating and supplying tractive power to a locomotive. Theterm “autonomous,” as used herein, refers to an APU that able to actindependently and control the internal operations of the APUindependently in response to external requests, and wherein the internalworkings of the APU are opaque or unknown to external control systems.Autonomous APUs and associated fuel assemblies are described inadditional detail in U.S. Non-Provisional patent application Ser. No.13/838,787, which is incorporated by reference herein.

APU 50 includes an auxiliary engine-generator set 82 having an engine 78and an auxiliary alternator or generator 84 that is electricallyconnected to an electrical manager 86, which manages the electricitygenerated by APU 50 and provides that electricity to a specificlocomotive 112 via a power cables 142. When APU 50 is connected to morethan one locomotive at a time, multiple electrical managers (one perconnected locomotive) may be used in order to electrically isolate eachlocomotive. In operation, APU controller 70 receives and responds torequests from locomotive control system 113 and may also provideperiodic or asynchronous notifications to locomotive control system 113.For example, APU controller 70 may report the presence or status of APU50 to locomotive control system 113, provide identifying informationabout one or more aspects of APU 50 (e.g., its identification type, aserial number), its engines 78 (e.g., engine type, rated horsepower,serial number), and the attached fuel assemblies 52 (e.g., fuel assemblyID, date of last pressure test). The APU controller 70 may furtherreport the amount of power the APU 50 is able to generate in response toa power request. APU controller 70 also receives signals from sensors 71located within APU 50 and may also receive instructions, such as a startrequest, an emergency stop request, and a power request from locomotivecontrol system 113, as described in additional below.

Optionally, APU 50 may be configured to provide identifying informationto intercept locomotive controller 162 via an optional control interface72 (shown in phantom in FIG. 4). This identifying information includesidentifying information from APU 50 as well as identifying informationfrom fuel assemblies 52 coupled to APU 50. Identifying information mayinclude an equipment configuration of APU 50, the amount and/or cost ofpower that is currently being generator and/or can be generated by theAPU 50, and a cost of fuel within the pressure tanks 60 of fuel assembly52 as examples. Based on the identifying information received from APU50 and a current total power demand of locomotive 112, interceptlocomotive controller 162 makes a determination as to how to allocatepower generation between locomotive engine-generator sets 116 andauxiliary power unit 50. According to one embodiment, APU 50 isprogrammed to periodically transmit identifying information to interceptlocomotive controller 162, such as, for example, (as a notification) atpredefined time intervals. Intercept locomotive controller 162 may alsocommunicate with one or more fuel assemblies 52 (as optional locomotiveequipment or via an APU 50 interface), which provide gaseous fuel to oneor more of the locomotive engines 118 and/or APU 50. Fuel assemblies 52also provide sensor information regarding fuel state, fuel type, andfuel costs to intercept locomotive controller 162.

Output power generated by auxiliary generator 84 is delivered to DC bus124 of locomotive 112 via power cables 100 and control cables 142, whichare coupled between APU assembly 48 and locomotive 112 via respectivecontactor boxes 206, 208. The number of control cables 100 is determinedbased on design specifications for the amperage and interconnectionbetween locomotive 112, APU 50, and fuel assemblies 52. As shown in FIG.2, a disconnect sensor 144 is coupled to power cables 142, whichelectrically connect locomotive 112 and APU 50. Disconnect sensor 144 isconfigured to sense a connection status of APU 50 with locomotivetraction bus 124. Should a decoupling occur between locomotive 112 andrail car 56 and/or a disconnection occur between power cables 142 andlocomotive traction bus 124, disconnect sensor 144 will transmit analert signal to at least one of APU controller 70, legacy locomotivecontroller 114, and intercept locomotive controller 162 indicating thedisconnection.

In some embodiments, intercept locomotive controller 162 provides APUcontrol instructions on an optional dedicated APU control interface 72(shown in phantom in FIG. 4). In a preferred embodiment, this controlinterface 72 provides signaling that is electromagnetic interference(EMI) resistant (e.g., CANbus). In other embodiments, control cables 100may include converters (described above) that convert locomotivecontroller engine control voltages (e.g., RPM, generator excitement)to/from EMI resistant signaling means. In other embodiments, controlcables 100 may include converters (not shown) to convert locomotivecontroller engine control voltages (e.g., RPM, generator excitement) toAPU controller instructions. These converters may be implementedindividually or in series as desired to provide a signaling path betweenthe intercept locomotive controller 162 and APU control interface 72.

The intercept locomotive controller 162 is optionally connected to oneor more fraction bus sensors 140 and meters via control and sensorcircuits. These sensors and meters monitor the amount of power placed onthe traction bus 124 by an APU 50. Similarly, an intercept locomotivecontroller 162 may provide a control circuit effective to control theoperation of an APU 50. When connected in this way, the controller 70 ofAPU 50 may receive instructions from the intercept locomotive controller162 to provide a specific amount power to the locomotive traction bus124 and/or the auxiliary power bus 126. For clarity of illustration, theconnections are shown for a single external power unit or APU 50.Sensors, meters, and control circuits may be replicated for each APU 50if a plurality of APUs 50 are utilized. Any control and/or sensorcircuit may optionally be electrically connected to a common control andsensor interface (not shown), which is electrically connected tointercept locomotive controller 162 in order to minimize the number ofdiscrete control and sensor circuits.

Referring now to FIGS. 3 and 4, the control system configuration andoperation of intercept locomotive controller 162 are described accordingto various embodiments of the invention. As referenced above anddescribed in detail below, the intercept locomotive controller 162 ispositioned between a legacy locomotive controller 114 and its locomotiveequipment, and receives and processes legacy locomotive controllerinstructions to the engines, alternator/generators, traction motorcontrollers, and other locomotive equipment, and transmits the same oraltered instructions to the locomotive equipment and one or more APUs50. The intercept locomotive controller 162 also receives responses andsensor inputs from one or more APUs and locomotive equipment, integratesthese responses, synthesizes any necessary information within processor166, and presents the integrated and/or synthesized information to thelegacy locomotive controller 114. According to various embodiments,intercept locomotive controller 162 is operable with digital, analog, ora combination of both digital and analog control and sensor inputs andoutputs.

Intercept locomotive controller 162 includes various interfaces thatpermit the intercept locomotive controller 162 to perform electronicmonitoring, control, and reporting of locomotive and APU operation. Forexample, intercept locomotive controller 162 includes one or morereceive engine interfaces 168, which are connected to the legacylocomotive controller 114 and receive engine and/or alternator/generatorsettings from the legacy locomotive controller 114. Collectively, thesesignals encode an amount of power requested by the legacy locomotivecontroller 114 of a power source, such as, for example, a specificengine and alternator/generator pair. According to various embodiments,intercept locomotive controller 162 may include one or more receiveengine interfaces 168 depending upon the number of power sources thelegacy locomotive controller 114 is controlling. Intercept locomotivecontroller 162 further includes one or more send sensor interfaces 170,which are connected to sensor inputs of the legacy locomotive controller114. The intercept locomotive controller 162 sends synthesized sensorvalues to the legacy locomotive controller 114 using this interface 170.

Intercept locomotive controller 162 also includes one or more sendengine/generator interfaces 172, which are connected to the controlinputs of the locomotive engine(s) 118 and generator(s) 120. It is overthese interfaces 172 that the intercept locomotive controller 162configures the engine and generator settings of the locomotive engines118. Intercept locomotive controller 162 further includes at least oneAPU command interface 174, which is operably connected to an APU 50 asdescribed herein. The intercept locomotive controller 162 communicateswith one or more APUs 50 over this interface 174.

Interfaces 172 and 174 connect interface locomotive controller 162 toengine/generator sets 116 and APUs 50 using control and sensor circuitsconstructed to convert the digital and/or analog singles from therespective power sources to/from a form usable by the interceptlocomotive controller 162. In some implementations, interface 172leverages control and sensor circuitry that is a portion of pre-existingwiring already present in the locomotive 112. In some implementations,the engine control circuitry includes engine RPM control circuits, thegenerator control circuitry comprises generator excitation controlcircuitry, and sensor inputs include engine RPM and generator outputreadings. Note that although the sensor inputs are illustrated as asingle circuit, alternative embodiments may include a plurality ofcircuits.

Intercept locomotive controller 162 additionally includes one or morereceive locomotive sensor input interfaces 176, which are operablyconnected to DC traction bus sensors 140 as well as one or moreadditional sensors 200 on the locomotive 112. According to variousembodiments, the number of locomotive sensor input interfaces 176 mayvary based on the number of sensors the legacy locomotive controller 114is provided with. Additional locomotive sensors 200 may include, asnon-limiting examples, such sensors as overheat, engine RPM, fractionmotor temperature sensors, traction motor power usage sensors, auxiliarybus power sensors, and the like. Optionally, the sensor inputs mayinclude an interconnection to the interface and/or user interface of theMU, which permits the intercept locomotive controller 162 to receivecontrol inputs from sources using the MU and/or user interfacecomponents (e.g., a throttle, brake level, or user interface panel)

The intercept locomotive controller 162 further optionally includes oneor more send locomotive equipment interfaces 178 connected to locomotiveequipment such as traction motors, traction motor controllers, or otherlocomotive equipment interfaces that are operably connected to thelocomotive equipment in order to permit the intercept locomotivecontroller 162 to control one or more locomotive equipment components.Optionally, the send locomotive equipment interfaces 178 may include aninterconnection to the MU interface and/or user interface 136 of thelocomotive 112, which permits the intercept locomotive controller 162 tosend control information to other locomotives using the MU and/or userinterface components (e.g., a user interface panel). While interceptlocomotive controller 162 is illustrated in FIG. 3 as including fiveinterfaces, one skilled in the art will recognize that the number ofinterfaces may be varied based on design specifications and systemconfiguration.

Intercept locomotive controller 162 also includes one or more memories164 within which intercept locomotive controller 162 may storeidentifying information used to uniquely identify legacy locomotivecontrollers 114 to which it is connected. This information may be usedfor the intercept locomotive controller 162 to configure its inputs andoutputs, and to configure power allocation and similar algorithms.Intercept locomotive controller 162 also may store information regardstandardized and specific locomotive equipment characteristics. Forexample, standardized information about locomotive equipmentcharacteristics may include a power curve specific to one or moreclasses of engines, information describing generating and/or powercapacity of one or more classes of auxiliary power unit assemblies,acceptable fuel types for use with a particular auxiliary power unit,shutdown delay interval, sensor types and value ranges/meaning, and thelike. Similarly, intercept locomotive controller 162 may store specificinformation about the locomotive within which it is installed, such asconnected locomotive equipment as well as operating requirements,parameters, control instructions, etc. associated with the respectivelocomotive equipment. For example, the information may include a list ofattached locomotive engines/generators, their capabilities and powercurves, fuel efficiency metrics for each of the specific engines,sensors connected and their expected values and ranges (and meanings ofthese values), and the like.

Intercept locomotive controller 162 may also store information about oneor more classes of auxiliary power units and/or a specific auxiliarypower units, including the capabilities of classes of auxiliary powerunits (e.g., capability, interconnect requirements, cost of power, fueltypes) and specific instances of auxiliary power units. Specificinformation stored may include information about one or more aspects ofa particular auxiliary power unit assembly (e.g., its identificationtype, a serial number), its engines (e.g., engine type, ratedhorsepower, serial number), and the attached fuel assemblies (e.g., fuelassembly ID, date of last pressure test), the cost of power provided bythe auxiliary power unit assembly, any limits on the use of power fromauxiliary power unit assembly, and information related to the operationof auxiliary power unit assembly, including historical sensor readings,power produced and delivered, and operation, inspection, and usehistory.

Within memory 164 of intercept locomotive controller 162, one or moreconfiguration tables are stored. These configuration tables includeinstructions for communicating with specific types and models ofengine/generators, external power units, sensors, and locomotive controlunits, including control parameters, input and output value ranges, andother related information. The memory 164 of intercept locomotivecontroller 162 may also include input/output interface parameters thatare used to associate specific interfaces with the intercept locomotivecontroller control logic, any adjustments in value used to interface tothose interfaces, and similar information. In some implementations, thememory 164 of intercept locomotive controller 162 may further includecontrol strategy information which is used by the intercept locomotivecontroller 162 to allocate power requirements across multiple powersources. For example, a simple control strategy might be to run thelegacy locomotive engine/generator set 116 at idle in order to producepower for the auxiliary bus 126, and supply all other power requirementsfrom the APU 50.

Memory 164 of intercept locomotive controller 162 may include aninternal database of legacy locomotive control systems and equipment,including engine/generator classifications and settings, legacylocomotive controller information, sensor types, etc. This informationis used by the intercept locomotive controller 162 to configure itsresponses to inputs and to properly configure its outputs. For example,the intercept locomotive controller database may include information onone or more legacy locomotive controller types, which may provideinformation as to its control outputs (which are connected to theintercept locomotive controller inputs), their expected values, and anyexpected responses and/or sensor values. The database may also associatea specific control regime or control plan for use with a specific legacylocomotive controller. Similarly, the intercept locomotive controllerdatabase may include information about:

a) engine/generator combinations, including control specifications forengine/generator settings required to produce specific power levels,expected sensors and sensor values associated with specificengine/generator performance, etc.,b) APU settings/command interface specifications, including APUidentification databases, APU class performance characteristics, APUcommand interface and response settings, including APU interface andprotocol specifications for communicating (e.g., sending commands,receiving responses) with one or more APUs,c) traction motor controller settings and related sensor values,including communication protocols used, control formats and settings toinstruct a fraction motor controller, and expected sensor values andtheir control interpretations for traction motors (temperature, powerused, etc.),d) fuel types and energy contents, for use with managing removable fuelassemblies,e) fuel assembly communications parameters, including communicationprotocols used, control formats and settings to instruct a fuel assemblycontrollers, and expected sensor values and their controlinterpretations,f) operating plan, including power allocation plans as described below,andg) locomotive equipment configurations, including type of equipment,corresponding inputs and output interfaces of the intercept locomotivecontroller 162, and conversion information.

In one embodiment, intercept locomotive controller 162 is a PLC ormicrocontroller, along with associated memories and volitile registersand as well as the associated digital and analog interfaces in orderprovide control electronics for the electronic monitoring, control andreporting of locomotive engine/generators and sensors.

Referring now to FIG. 4 and with continued reference to FIG. 2 and FIG.3, the operation of intercept locomotive controller 162 within thecontext of the locomotive consist 110 is set forth. The legacycorrelation between primary engine RPM (or throttle setting) and theamount of electricity generated is stored within legacy locomotivecontroller 114. Legacy locomotive controller 114 manages the amount ofapparent power present on the busses 124, 126 by requesting changes inengine RPM and generator excitement (e.g., by changing the controlsignals) and by measuring the amount of power reported by the interceptlocomotive controller 162 as being present on the various busses 124,126. Legacy locomotive controller 114 also calculates and manageslocomotive location and anticipated power needs and issues adjustedpower configurations to the locomotive equipment. These adjusted powerconfigurations are intercepted by the intercept locomotive controller162 and further adjusted to integrate the use of one or more APUs 50.

In operation, intercept locomotive controller 162 periodically receivesengine/generator control signals indicating requested engine RPM andgenerator excitement from legacy locomotive controller 114 throughengine control interface 168. Whether the engine control signal receivedis continuous or episodic depends upon the engine/generator(s) 118, 120and legacy locomotive controller 114 installed in the locomotive. Uponreceipt of an engine/generator control signal, intercept locomotivecontroller 162 compares the current state and value(s) of theengine/generator control signal(s) against a previous state of theengine/generator control signal(s) to determine if one or more of thevalues have changed from previous settings. If there are no differencesfrom the previous engine/generator control signal(s), then the interceptlocomotive controller 162 does not initiate any changes in its settings.If, on the other hand, there are changes in the engine/generator controlsignal(s) received, the intercept locomotive controller 162 may take oneor more of the following actions:

A) look up the engine control interface type in an intercept locomotivecontroller 162 memory to determine the meaning of the control signal(s)received. This permits the intercept locomotive controller 162 tocalculate the amount of power the legacy controller 114 is requestingfrom the respective engine/generator set 116;B) calculate the change in power requested, and perform a powerallocation (or other) operation between two or more power sources, suchas, for example, engine/generator set 116 and APU 50 as describedherein;C) store the results of the power allocation (or other) operation forsubsequent use in processing sensors; andD) output engine/generator control signals and APU control signals tothe send engine/generator interface 172 and to the APU control interface72 via interface 174 in accordance with the results of the powerallocation operation in order to cause the power sources to provide theallocated amount of power or perform other operations.

Similarly, the intercept locomotive controller 162 intercepts signalsfrom power sensors 140, and locomotive engine/generator sensors 122 thatindicate operational information for the locomotive control system 113,such as, for example, on the amount of power actually provided by APUs50, and the settings and/or operational conditions of other locomotiveequipment, and the status and/or operation of locomotiveengine-generator set 116 (e.g., various parameters of engine 118 such asrevolutions-per-minute (RPMs), operating power output, temperature andother engine operating parameters). The intercept locomotive controller162 receives this information through sensor interface 176, integratesthe information to an integrated set of sensor values (possibly changingtheir values or providing synthesized values), and forwards theintegrated and synthesized sensor reading(s) to the legacy locomotivecontroller 114 and locomotive equipment through sensor interface 170.The intercept locomotive controller 162 permits the legacy locomotivecontroller 114 and existing locomotive equipment (e.g., locomotiveengine generator set 116) to operate as “normal”, while providingadditional features such as the integration of one or more APUs 50 tothe locomotive consist 110.

Whether the sensor signal received by intercept locomotive controller162 through sensor interface 176 is continuous or episodic, or in analogor digital form, may vary depending upon the sensor being monitored.Upon receipt of an engine/generator control signal, the interceptlocomotive controller 162 compares the current state and value(s) of thesensor signal(s) against a previous state of the sensor signal. If thereare no differences from the previous sensor signal(s), then theintercept locomotive controller 162 does not initiate any changes in itssettings. If there are changes in the sensor signal received, theintercept locomotive controller 162 takes the following steps:

A) look up the sensor information describing the sensor values andmeanings;B) determine other sensor input values expected, and obtain sensorsvalues for those sensors as well;C) create a synthesized sensor value from the input values consistentwith the expected sensor output to the legacy locomotive controller 114;D) output the synthesized sensor value to the appropriate send sensorinterface 170 (as determined by the locomotive equipment (sensor)configuration information stored in the intercept locomotive controller162); andE) execute power allocation or other controller functions to manage thelocomotive equipment in conjunction with one or more APUs 50.

As one example, intercept locomotive controller 162 receives signalsfrom DC bus sensors 140, engine-generator sensors 122 and, optionally,other locomotive sensors 200. The sensor values from the DC bus sensors140, engine-generator sensors 122, and other locomotive sensors 200 arecompared against the operating plan of the intercept locomotivecontroller 162 (and adjustments are made to settings if necessary), andthe sensor values are combined to produce synthetic sensor values fortransmission to the legacy locomotive controller 114 indicating that thelocomotive engine/generators 118, 120 are producing the requested ordesired amounts of tractive power.

Intercept locomotive controller 162 includes an Excitation Split moduleand a Feedback Join module as part of its control logic. The ExcitationSplit module of intercept locomotive controller 162 takes the excitationrequests from the legacy locomotive controller 114 received via engineinterface 168, determines the power equivalents of the excitationrequests from a configuration table, performs a power allocationprocess, and distributes the power allocation instructions between oneor more APUs 50 and one or more diesel generator/alternator sets 116 ofthe locomotive 112. The Excitation Split module also uses as an inputvalues from the APU 50 that indicate the available power from the APU 50and from the configuration information of the intercept locomotivecontroller 162, which identifies the excitation/RPM/power producedinformation for each engine/generator set 116.

The Excitation Split module uses the available power from the APU 50 todetermine how much of the excitation request to distribute to each ofthe engine/generator set 116. The nominal case is to distribute as muchpower as possible to the APU 50. Some embodiments may make alternatedeterminations based upon emissions requirement, fuel costs, etc. If theAPU 50 is not present, the available power from the APU is zero and theExcitation Split module distributes all excitation requests to theavailable diesel engine/generator sets 116. In this instance, theintercept locomotive controller 162 is fully backwards compatible withthe legacy diesel-only system.

The Feedback Join module of intercept locomotive controller 162 sums thecurrents from the alternator 120 and other power sensors connected tothe intercept locomotive controller 162 and provides an integrated(synthesized) signal to legacy locomotive controller 114. The legacylocomotive controller 114 thus functions identically to how it didbefore. The function of the legacy locomotive controller 114, which isto compare the system power against the power set-point, remainsunchanged with the addition of intercept locomotive controller 162.

According to various embodiments, the multiple power sources includedwithin locomotive consist 110, including locomotive engine-generatorset(s) 116 and APUs 50, may be configured to add energy to the DC bus124 via passive rectification, active rectification, and/or DC Bus PulseWidth Modulation, as described below. Each of these methods assume aparallel bus architecture. Alternative embodiments using a seriescircuit involve wiring the alternators in series would require thatevery alternator we add be capable of passing the entire system current,which may make the alternator prohibitively expensive and large. Whenusing a series circuit, there are no rectifiers to contend with, thefinal power given to the system is simply the current multiplied by thesum of voltages of each generator 120.

In one embodiment, power from locomotive engine-generator set(s) 116 andAPUs 50 are shared on the DC bus 124 using passive rectification. Inthis implementation, the electrical systems of the APU 50 is configuredsimilarly to the electrical system of the locomotive 112, such as, forexample, a rectified fraction alternator feeding DC bus 124. The fieldcoil to the APU 50 is driving by a pulse-width-modulated chopper circuitthat can excite the APU 50 and that is not subject to the waveform phasedelays that a silicon controlled rectifier (SCR) system is. In thisembodiment, whichever generator has the highest voltage at anyparticular time is the one driving the DC bus 124. Since there is rippleof about 15% in the rectified voltage of the DC output, multiple powersources will drive some power if their voltage is within 15% of thehighest voltage source.

In another embodiment, power sharing between locomotive engine-generatorset(s) 116 and APUs 50 is effected through active rectification. In thisembodiment, an AC-DC converter having a voltage rating on the kilovoltscale and a power rating on the megawatt scale is included withinlocomotive assembly 110. The voltage of each APU 50 is controlledthrough active rectification with the target voltage being enough todrive the desired proportional power of the system. Excitation requestsfrom the Feedback Split module of intercept locomotive controller 162step up the voltage of the APU 50 while lack of excitation requestsslowly lowers the voltage.

Power sharing may also be implemented between locomotiveengine-generator set(s) 116 and APUs 50 through a high-voltage,high-power switch provided on each APU 50. The APUs 50 are then operatedat a voltage that is higher than the voltage of the DC bus 124.Excitation requests from the Feedback Split module of interceptlocomotive controller 162 close the switch momentarily and DC powerflows from the higher-voltage APU 50 onto the DC bus 124. Modulating thesystem determines how much energy is added to the DC bus 124.

One important aspect of handing the APU controller 70 is response timeto requests from the intercept locomotive controller 162. Locomotivecontrollers operate in very short duration control loops, and responsetime of APUs to locomotive controller requests is important to thesuccessful operation of a locomotive control with an autonomous APU 50.Accordingly, in one embodiment the APU controller 70 provides responsetimes to requests received from the intercept locomotive controller 162within a configuration defined amount of time or be considerednon-responsive. A non-responsive APU controller would be considered afault condition by the intercept locomotive controller 162 and behandled accordingly. Some locomotive controller requests may contain anindication that the request should be handled quickly (e.g., within 10msec, 100 msec, 1 sec, or 10 sec, depending upon the type of change),such as power removal requests being generated in conjunction with wheelslip or fault events. Other operational issues, such as fuel amountscrossing a lower threshold, chassis temperature or alarms, for example,can be handled more slowly. Still other operations, particularly thosethat include communications interactions with fuel assemblies or lengthycalculations, may complete in 10 or more seconds.

In one embodiment, the locomotive consist 110 may be operated to blendpower generated from the APU 50 and engine/generator sets 116. Blendingpower is advantageous when the transition of power must be seamless,when the locomotive control system 113 operates with a limited rate ofcontrol changes, or when one power source has operationalcharacteristics (e.g., response time) where changes in power providedcannot be reflected within operationally acceptable response times.

In such an embodiment, a second power source can be configured to“follow” a first power source in accordance with a power allocationplan. For example, if a first power source has a high electrical inertiacompared to a second power source, changes in electric power demandsthat require quick responses (such as wheel slip responses) may bepreferentially allocated to the power source that is able to morequickly respond, followed by an optional follow-up set of powerreallocation to balance loads between the power sources to more fuelefficient and/or cost effective power allocations.

For example, if the APU 50 responds more slowly to a change in powerthan locomotive engine/generator, changes in power demand will behandled by the locomotive control system 113, with power allocation andsubsequent commands to the APU 50 and request to the locomotive'sengine/generator occurring at different times. The locomotive controlsystem 113 may first configure the engine/generator set 116 of thelocomotive 112 to quickly produce a differing amount power in responseto a changed power request (either up or down) in order to meet thereceived power request, followed by a subsequent APU controller 70commands to change the amount of power generated by the APU 50, followedby an (optional) third change in the locomotive engine/generatorsettings to “trim” the amount of power provided to the locomotiveconsist 110 to again match the original power request (in light of thechanged APU power generation in response to the APU commands). If theresponse times/inertial response of the power units differ, the orderand timing of requests and commands may vary.

In some embodiments, the intercept locomotive controller 162 isprogrammed to operate in accordance with one or more defined operatingplans, which instruct the intercept locomotive controller 162 on how toperform power allocations. The operating plan(s) may be implemented inthe control logic of the intercept locomotive controller 162, as aprogram element implemented by the processor 166 of the interceptlocomotive controller 162, implemented as a control plan executed by thelogic of intercept locomotive controller 162 and stored in a memory 164or as part of the operating plans of the internal database of memory164.

According to one embodiment, the operating plan of intercept locomotivecontroller 162 is defined as a look-up table that allocates powerbetween the legacy engine 118 and APU 50 based upon an input ofrequested engine RPM. As one example, illustrated in TABLE 1 below, theintercept locomotive controller 162 outputs two values based on thereceived engine RPM input: an RPM for the legacy engine 118 and a powersetting for the APU 50.

TABLE 1 Input Output Engine RPM Legacy engine RPM APU setting 164 164   0 kW 400 164  152 kW 500 350  400 kW 600 400  600 kW 700 450  800 kW800 500 1000 kW

According to another embodiment, the operating plan of interceptlocomotive controller 162 is defined as a look-up table, such as, forexample, TABLE 2 below, that changes the excitation voltage of legacylocomotive engine 118 to reduce load (and power output) while keepingRPMs raised in order to support direct drive operation.

TABLE 2 Output Input Legacy engine Excitation APU Engine RPM RPM Voltagesetting 164 164 5.0 V    0 kW 400 350 4.0 V  152 kW 500 400 3.0 V  400kW 600 450 2.0 V  600 kW 700 500 1.0 V  800 kW 800 600 0.5 V 1000 kW

An exemplary interface definition table that describes the actions ofthe intercept locomotive controller 162 with respect to intercept andforwarding of sensor values is provided in TABLE 3 below, in accordancewith one embodiment of the invention. As described in additional detailbelow, TABLE 3 defines the sensors connected to various receive sensorinterfaces of the intercept locomotive controller 162, and the actionsto be taken by the intercept locomotive controller 162 under variousoperating conditions. It is contemplated that the intercept locomotivecontroller 162 additionally may take other actions to manage thelocomotive 112 and/or APU 50 as described herein.

Initially, it is contemplated that the multiple receive engineinterfaces and receive locomotive equipment interfaces listed TABLE 3below may be incorporated within respective multi-input interfacesprovided on intercept locomotive controller 162 or individual inputinterfaces, such as, for example, control interface 168 (FIG. 3) andsensor interface 176, according to alternative embodiments. Further,according to various embodiments the sensor signals listed in theDisposition column of TABLE 3 may be forwarded from a common send sensorinterface, such as send sensor interface 170 (FIG. 3), or from a numberof individual send sensor interfaces provided on intercept locomotivecontroller 162.

TABLE 3 Control- Report Line Sensor ID Model Interface Disposition 1Engine RPM Cummins Receive On change, calculate instructions Enginepower requested, Interface 1 allocate power to consist 2 GeneratorCummins Receive On change, calculate excitement Engine power requested,instruction Interface 2 allocate power to consist 3 Fault MU ReceivePoll 1s, on change, Locomotive process fault Equipment 0 4 TractionTempSensor Receive Poll 1s, on change, Motor Locomotive send to sendsensor Temperature Equipment 1 interface 5 Traction PowerSensor ReceiveOn change, calculate Motor Draw Locomotive reported power, set Equipment2 value to calculated power and send to send sensor interface 6 DC busPowerSensor Receive On change, recalculate power Locomotive powerprovided, send Equipment 3 calculated power to send sensor interface 7Engine 1 Cummins Receive On change, recalculate RPM Locomotive power,send calculated Equipment 4 RPM to send sensor interface, process powerchange 8 Generator 1 Cummins Receive On change, set to voltageLocomotive requested power for Equipment 5 engine/generator and forwardto send sensor interface, process power change 9 APU power PowerSensorReceive On change, calculate Locomotive reported power and Equipment 6engine 1 RPM sensor values (synthesize) and send to send sensorinterface, process power change 10 APU APU ID APU On receipt, processCommand response Interface

In TABLE 3, Line 1 indicates that engine RPM instructions are present onReceive Engine Interface 1, which refers to the intercepted engine RPMcontrol instruction from the legacy locomotive controller 162. Theaction(s) that the intercept locomotive controller 162 takes in responseto this instruction are: (1) calculate the power request, and (2)allocate power requests to the locomotive consist 110. These actions aredescribed in additional detail elsewhere herein.

Line 2 of TABLE 3 indicates that generator excitement instructions willbe present on Receive Engine Interface 2. These generator excitementinstructions are the intercepted generator excitement voltage from thelegacy locomotive controller 114. The action(s) that the interceptlocomotive controller 162 takes in response to these instructions are:(1) calculate the power request, and (2) allocate power requests to thelocomotive consist 110. These actions are described in additional detailelsewhere herein.

In an exemplary embodiment, the above-referenced RPM instructions andgenerator excitement instructions are received in the Cummins6500format, however, one skilled in the art will recognize that theinstructions may be received in alternative formats.

Line 3 of TABLE 3 indicates an exemplary connection by the interceptlocomotive controller 162 to pre-existing fault circuitry within thelocomotive 112 using the Receive Locomotive Equipment 0 interface. Inthis exemplary connection, the fault sensor is tied to the MU interfacefault line and uses the MU signaling standard, however, embodiments ofthe invention are equally applicable to alternative signaling standards.The intercept locomotive controller 162 is configured to periodicallypoll the interface, register a change in voltage on this interface as afault, process that fault, and forward the fault indication to otherlocomotive systems on send sensor interface 170.

Line 4 of TABLE 3 indicates an exemplary intercept by the interceptlocomotive controller 162 of a traction motor temperature sensor on theReceive Locomotive equipment 1 interface. The traction motor temperaturesensor is configured as reporting using a known temperature sensorreporting mechanism (shown as the control-reporting model “TempSensor”).The intercept locomotive controller 162 is configured to poll thisinterface periodically, and report changes by echoing them to the legacylocomotive controller 162 on a send sensor interface 170.

Line 5 of TABLE 3 indicates an exemplary intercept by the interceptlocomotive controller 162 of a traction motor power draw sensor on aReceive Locomotive Equipment 2 interface. The power draw sensor reportspower using a known power reporting mechanism (shown as thecontrol-reporting model “PowerSensor”). The intercept locomotivecontroller 162 is configured to detect a change in the reported value,recalculate the amount of reported power in accordance with the amountof power the legacy locomotive controller 114 is expecting to see on thebus 124, and send the calculated amount of reported power encoded usingthe “PowerSensor” scheme to the legacy locomotive controller 114 on asend sensor interface 170.

Note that in this exemplary embodiment the intercept locomotivecontroller 162 is passively managing the traction motor draw andtemperature in order to cause the legacy locomotive controller 114 toproperly manage cooling of the traction motor 128. In other embodiments,the intercept locomotive controller 162 may be configured to receive atraction motor temperature and/or a traction motor power draw value,calculate the amount of cooling required, and directly control thetraction motor 128 and/or traction motor blower 204. This illustratesthe flexibility of the intercept approach to managing a legacylocomotive.

Line 6 of TABLE 3 indicates an exemplary intercept of the DC bus powersensor 140 by the intercept locomotive controller 162 on the ReceiveLocomotive Equipment 3 interface. The DC bus power sensor 140 reportspower using a known power reporting mechanism, referred to herein as thecontrol-reporting model “PowerSensor”. The intercept locomotivecontroller 162 is configured to detect a change in the reported value,recalculate the amount of power available to the locomotive 112 usingprevious power requests from the legacy locomotive controller 114, andtransmit the recalculated sensor value to the legacy locomotivecontroller 114 on send sensor interface 170. Note that the amount ofpower reported to the legacy locomotive controller 114 may be replaced,scaled, or similarly adjusted to provide “expected” values of DC buspower to the legacy locomotive controller 114.

Line 7 of TABLE 3 indicates an exemplary intercept of the first engineRPM sensor by the intercept locomotive controller 162 on a ReceiveLocomotive Equipment 4 interface. As one non-limiting example, thesignals from the first engine RPM sensor may be encoded using a knownEngine RPM encoding scheme, such as, for example, a Cummins encodingscheme. The intercept locomotive controller 162 is configured to receivea changed value on this Receive Locomotive Equipment 4 interface, adjustthe reported value to report the expected engine RPMs in accordance witha previously requested engine RPMs and the amount of power received fromother sources (e.g., APUs 50), and to forward the calculated RPMs valueto the legacy locomotive controller 114 using a send sensor interface170. The intercept locomotive controller 162 then processes a change inpower provided by the engine/generator set 116 as described herein.

Line 8 of TABLE 3 indicates an exemplary intercept of the firstgenerator excitement sensor by the intercept locomotive controller 162on a Receive Locomotive Equipment 5 interface. As one non-limitingexample, the signals from the first generator excitement sensor may beencoded using a known generator excitement voltage scheme, such as, forexample, a Cummins encoding scheme. The intercept locomotive controller162 is configured to receive a changed value on this Receive LocomotiveEquipment 5 interface, adjust the value received to a value expectedbased upon the requested power/excitement of the generator, and forwardthis synthesized value to the legacy locomotive controller 114 on a sendsensor interface 170. The intercept locomotive controller 162 thenprocesses a change in power provided by the engine/generator set 116 asdescribed herein.

Line 9 of TABLE 3 indicates an exemplary intercept of an optional APUpower sensor by the intercept locomotive controller 162 on a ReceiveLocomotive Equipment 6 interface. The APU power sensor reports powerusing a known power reporting mechanism, referred to herein as thecontrol-reporting model “PowerSensor”. The intercept locomotivecontroller 162 is configured to detect a change in the reported value,recalculate the amount of power available to the locomotive 112 usingprevious power requests from the legacy locomotive controller 114,synthesize sensor values for other power source sensors, and to forwardthese synthesized sensor value to the legacy locomotive controller 114on a send sensor interface 170. The intercept locomotive controller 162then processes a change in power provided to the locomotive 112 asdescribed herein.

Line 10 of TABLE 3 refers to signals transmitted over the interfacebetween the intercept locomotive controller 162 and an APU 50 using anAPU Identification interface standard through which the interceptlocomotive controller 162 receives identifying information andoperational information from the APU 50. Upon receipt of a notificationor status report from the APU 50, the intercept locomotive controller162 responds by processing the notification/status report as describedherein. Depending upon the report, it may synthesize one or more sensorreadings and output them to one or more send sensor interfaces 170configured for the intercept locomotive controller 162.

According to various embodiments of the invention, an interceptlocomotive controller, such as intercept locomotive controller 162, maybe implemented within legacy locomotive systems in a number of ways. Inone embodiment, an intercept locomotive controller is interfaced with apre-existing (legacy) digital locomotive controller. The digitallocomotive controller receives digital signal inputs and producesdigital signal and control outputs that are translated into engine,generator, and other component actions when they are received by thecontrolled component. The intercept locomotive controller interceptssensor signals and control outputs from the digital locomotivecontroller by receiving a digital signal transmitted to the digitallocomotive controller, decoding that signal, creating replacementencoded digital signals to be transmitted to the digital locomotivecontroller. In an alternative embodiment, an intercept locomotivecontroller is interfaced with a pre-existing analog electro-mechanicallocomotive controller. The pre-existing analog controller receivesanalog signal inputs characterized as voltages, amperages, and/orwaveforms proportional to their sensor readings and produces analogsignal and control outputs characterized by voltages, amperages, and/orwaveforms proportional to the desired control actions that aretranslated into engine, generator, and other component actions when theyare received by the controlled component. Examples of these waveformsinclude amplitude modulation, frequency modulation, and hybrid schemessuch as pulse-width-modulation (PWM). The intercept locomotivecontroller intercepts the sensor signals and control outputs byreceiving an analog signal, decoding that signal and translating it soit may be acted upon by the intercept locomotive controller, and thencreating replacement analog signals reflecting the control intent of theintercept locomotive controller. In yet another alternative embodiment,the intercept locomotive controller is interfaced to a pre-existing(legacy) analog or digital “genset” locomotive controller. Gensetcontrollers differ from a traditional locomotive controller in that theysupport more than one engine/generator set.

In each of the above-described implementations, the intercept locomotivecontroller 162 is electrically connected between the control outputs ofthe legacy locomotive controller 114 and the engine/generator set 116 ofthe legacy locomotive 112. The intercept locomotive controller 162receives control signals from the legacy locomotive controller 114,receives inputs from external power sources or APUs 50, and inputs fromsensors attached to the traction bus 124 and/or traction motors 128.Optionally, the intercept locomotive controller 162 may also beinterconnected so as to receive other inputs, such as inputs fromgenerator-based sensors 122. The intercept locomotive controller 162uses these inputs to determine the desired control adjustments,determines the attributes of modified control and sensor signals, andthen transmits modified control signals to the engine/generator set 116in order to configure the amount of power generated by the legacylocomotive engine/generator set 116.

Optionally, the intercept locomotive controller 162 also transmitscontrol signals to an APU 50 (and APU controller 70) via control cables100 in order to set or control the amount of power generated by the APU50. Intercept locomotive controller 162 is also programmed to generate atraction motor command that is configured to maintain desired orrequested levels of tractive power to the traction motors 128 consistentwith the (implied intent) of the original control signal from the legacylocomotive controller 114. The intercept locomotive controller 162 mayalso modify or generate other signals that are passed to the legacylocomotive controller 114 in order cause the legacy locomotivecontroller 114 to behave as if it were connected directly to theengine/generator set 116 without the intercept locomotive controller 162or the external power provided by the APU 50. The power produced by APU50 is then transmitted to locomotive traction bus 124 via power cables142.

In the case of a fault of a locomotive engine/generator 118, 120, thefault may be reported by the intercept locomotive controller 162 to theuser interface 136, and/or the legacy locomotive controller 114. In someimplementations, the fault is reported only to the user interface 136,and the power allocation function of the intercept locomotive controller162 requests additional power from other engines 118 and/or APUs 50 tomake up for the loss of power from the fault. In this case, theintercept locomotive controller 162 will report that the engine 118 inrunning normally (RPM, power produced, power on the bus) when it hasactually failed. If additional power is obtained from other locomotiveequipment engines 118 (for example, by raising their engine RPMs), theirsensor values are similarly adjusted to report that they are operatingas previously instructed.

According to one embodiment, at least one of APU controller 70 and atleast one of legacy locomotive controller 114 and intercept locomotivecontroller 162 are configured to detect a fault in the transmission ofpower and/or control commands through control cables 100. In someembodiments, upon detection of the fault, intercept locomotivecontroller 162 may forward the fault indication to legacy locomotivecontroller 114. The intercept locomotive controller 162 may beconfigured take one or more actions in response to the fault condition.If the fault condition is in the control cable connection 100 between alocomotive controller (either 114, 162, or both) and APU 50, exampleactions may include: resend one or more the power and/or controlcommands to APU 50, send a status command to APU 50, read one or moresensors and make a determination of the seriousness of the faultcondition, alert the locomotive operator thru a display or alertingdevice (e.g., light, alarm signal), forward the fault to anotherlocomotive controller. Other actions may be programmed into theintercept locomotive controller 162 in response to communications faultsbetween intercept locomotive controller 162 and APU 50 as would beunderstood by those skilled in the art. Alternatively, or in additionthereto, intercept locomotive controller 162 may be programmed to modifya previously sent power command upon detection of the fault, or to setAPU 50 to an “unavailable” status and reallocate power requirementsallocated to APU 50 to other engine/generator sets within the locomotiveconsist 110. For example, if APU 50 is showing a connection fault on itscommand circuit and it is not providing power to the power bus 124 asindicated by power bus sensors 140, intercept locomotive controller 162may decide that APU 50 is no longer functioning and reallocate the powerrequirements allocated to APU 50 to a primary locomotiveengine/generator set 116, causing it to increase its RPMs and alternatorexcitement voltages in order to provide the missing power to the powerbus 124.

In some implementations, the intercept locomotive controller 162 mayreport an APU 50 as an additional (phantom) primary engine/generatorcombination, and interpret legacy controller power control informationto that “phantom” engine/generator as instructions to the APU 50. Inthese cases, the intercept locomotive controller 162 serves as aprotocol converter that converts engine/generator control informationto/from the command protocol of the APU 50. In addition, the interceptlocomotive controller 162 may handle APU disconnects (or simply anunconnected APU) by reporting that the engine has been derated, hasfailed, or that it has failed to respond to the control inputs.

In some instances, intercept locomotive controller 162 is expecting aresponse from APU controller 70 that is not received, or is receiving inan unusable form. In this case, intercept locomotive controller 162 maytake one or more actions to respond to the missing response. Forexample, these actions may include any or all of the following: resendone or more the power and/or control commands to APU 50; send a statuscommand to APU 50; read one or more sensors and make a determination ofthe seriousness of the fault condition; alert the locomotive operatorusing a display or alerting device (e.g., light, alarm signal), generatea fault to another locomotive controller, generate a fault on one ormore interfaces (such as the MU interface). Other actions may beprogrammed into intercept locomotive controller 162 in response tocommunications faults between intercept locomotive controller 162 andAPU 50 as would be understood by those skilled in the art.

In other instances, intercept locomotive controller 162 may receivenotifications from APU controller 70 asynchronously. These notificationsmay comprise event or alert notifications, or may simply compriseinformation provided by APU controller 70 that intercept locomotivecontroller 162 may consider in managing locomotive consist 110. Theactions taken by intercept locomotive controller 162 in response tothese notifications may include any or all of the following: do nothing,send a command to APU controller 70 requesting additional informationabout APU controller memories 98; process the received information as afault indication or as a connection notification; process the receivedinformation as a sensor reading related to APU operation; store thereceived information in intercept locomotive controller memory 146 foruse during power cost calculations; store the received information inlocomotive controller memory 146 for use in subsequent power allocationcalculations; recalculate the cost of power provided by APU 50 for usein power allocation decisions; reallocate power allocation to APU 50;and command APU 50 to provide a differing amount of power to locomotivepower bus 124. Other actions may be programmed into intercept locomotivecontroller 162 in response to notifications received by interceptlocomotive controller 162 from APU 50 as would be understood by thoseskilled in the art.

Intercept locomotive controller 162 may recognize that something isconnected to its control line based upon the presence or absence ofvoltage, current or capacitance on the line. Upon recognizing theconnection of a new device to the locomotive control line (and theconnection of the power and control circuits or cables), interceptlocomotive controller 162 undertakes the following steps to determineinformation about APU 50: A) communicate with the device to determine ifindicated connection was to an APU, a fuel assembly, or some otherdevice, and if the device is not an APU or fuel assembly, interceptlocomotive controller 162 takes an action consistent with a faulthandling (as described above); B) intercept locomotive controller 162sends a command to the device to determine device identifyinginformation and receives a response, and if a response is not received,it is handled as described above; C) intercept locomotive controller 162optionally sends additional commands to the device and receivesadditional responses from the device to determine additional informationabout the device, or looks up information about the device, either in alocal memory or from a remote computer, to determine the additionalinformation, D) intercept locomotive controller 162 stores theinformation received in memory 146 for subsequent use; and E) based uponthe type of device connected, intercept locomotive controller 162 takesadditional actions selected from the set of actions: perform power costcalculations, perform power allocation, send a power command to APU 50,and select a fuel assembly.

Intercept locomotive controller 162 performs power cost calculations asthe cost of providing power changes. In an embodiment, the power costcalculation is a scalar value provided by an external device, acalculation based upon the cost of fuel and a conversion factorindicative of the power source's efficiency of converting a unit of fuelinto power (e.g., kilowatts per gallon). The calculations can alsoutilize the energy content of fuel provided. In some embodiments, thecalculations produce a scalar value. In others, the calculations producean n-dimensional based upon one or more engine performance metrics(e.g., amount of power produced, engine RPM, generator excitementvoltages, one or more metrics related to the fuel being used (price offuel, energy content of fuel), and one or more metrics related tooperating conditions (e.g., temperature, air pressure). The results ofthese calculations are stored in intercept locomotive controller memory146 for further use.

Intercept locomotive controller 162 sends a power command to APUcontroller 70 instructing it to provide a specific amount of power tothe power bus 124. Optionally, this power command may include anindication that the power command should be performed quickly, such aswhen intercept locomotive controller 162 is processing wheel slip orfaults. The power command send to APU controller 70 typically differsfrom normal engine control voltages in that it specifies an amount ofpower (current and voltage) to provide because intercept locomotivecontroller 162 is generally unaware of the power source settingsassociated with providing a desired amount of tractive power. Becauseintercept locomotive controller 162 is unaware of these settings,intercept locomotive controller 162 can interoperate with APUs 50 usingdiffering power sources. This provides a significant operationaladvantage.

After intercept locomotive controller 162 sends a power command to APUcontroller 70, APU controller 70 responds to intercept locomotivecontroller 162 in several ways. First, APU controller 70 responds to thepower command with a response on the control cable connection 100 to therequesting intercept locomotive controller 162. If intercept locomotivecontroller 162 does not receive the response within a configurationdetermined timeframe, intercept locomotive controller 162 takescorrective action as described above for missed response. Secondly,intercept locomotive controller 162 monitors sensors 140 on power bus124 to determine if APU 50 as provided the requested power. If the powerrequested does not appear on power bus 124 within a configurationdetermined, or dynamically determined timeframe, intercept locomotivecontroller 162 handles this failure to respond as a fault (as describedabove).

One aspect of intercept locomotive controller 162 is to managelocomotive consist 110 with respect to overall emissions produced. APUs50 may provide to intercept locomotive controller 162 information(graphs or scalar metrics) that represent the emissions produced or withrespect to emissions produced by each engine. In order to obtainemissions levels which adhere within certain limits or which bettermatch certain target objectives, intercept locomotive controller 162 maydetermine that APU 50 should operate using a certain balance of one fuelin preference to another (e.g., natural gas as opposed to syngas), or touse a certain mix of the two fuels over a particular time scale. Forinstance, a locomotive consist may not be able to achieve desiredmanagement of both NOx and particulate matter emissions over a certaindistance or time by running natural gas 100% of the time. Interceptlocomotive controller 162 makes this determination based upon higherlevel calculations based in part upon the emissions profile of the powersources available to intercept locomotive controller 162, theiremissions profile under particular load conditions, fuels available, andthe location of locomotive consist 110 and its projected loadconditions. Intercept locomotive controller 162, when making thesecalculations, adds the steps of sending a request to one more of the APU50, fuel assemblies 52 to determine the fuel types and emissionsprofiles for power requests to APU 50. Intercept locomotive controller162 receives the requested information, stores it in memory 146, andthen uses processor 116 to calculate the emissions profiles. Once theemissions profiles are calculated, intercept locomotive controller 162makes a determination regarding fuels to use and power allocations, andinstructs APU 50 and/or fuel assemblies 52 appropriately.

In some implementations, the intercept locomotive controller 162 isprogrammed with the legacy locomotive controller type, sensor types andinterface connections (and expected ranges), engine/generatortypes/control parameters and interface connections, and similarinformation. This information may be programmed in when the interceptlocomotive controller 162 is installed, or it may be preprogrammed intothe controller itself. Optionally, the intercept locomotive controller162 may interrogate attached devices to determine the informationrequired. In some implementations, the intercept locomotive controller162 may observe the control signals and/or presented by portions of thelocomotive control system 113 and determine the appropriate settings bylooking up observed information in an internal database of observedsettings. The auxiliary power enabled locomotive control system 113,including a legacy locomotive controller 114 and an intercept locomotivecontroller 162, is able to make power allocations between power sources.The auxiliary power enabled intercept locomotive controller 162specifically is able to determine if an APU 50 is connected, and if so,use APU 50 as one of the available power sources by integrating theoperations of the APU 50 into the locomotive operations by interceptingcontrol information and sensor inputs and creating synthesized controlinformation.

Intercept locomotive controller 162 is coupled to a memory module 146within which is stored its current cost of producing power using thestandard power. The current costs of producing power may be a uniquenumber, or may be a sequence of numbers stored in a look-up table basedupon engine RPM. In one embodiment, memory module 146 also stores aprice of fuel for locomotive engines 78. This price can be manually orelectronically updated on a periodic basis. Intercept locomotivecontroller 162, using this table, and the known engine RPMS, can computethe cost of providing a unit of power to the locomotive's tractionand/or auxiliary power busses 124, 126. This cost is called the internalgeneration cost.

Knowing the current cost of power, intercept locomotive controller 162may then seek lower cost power from APU 50 when APU 50 is able toprovide power for the locomotive busses 124, 126 at costs below theinternal generation cost. Intercept locomotive controller 162 reads thecurrent power cost from APU controller 70, and compares the internalgeneration cost to the price provided by APU controller 70, and selectsengine control points (and engine/generator settings) and APU powersettings to obtain power from at least one of the lowest cost source anda combination of sources whose costs aggregate to the lowest total cost.In some cases, this means intercept locomotive controller 162 will powerdown the engine/generator sets 116 and use only power produced by APU50. In other cases, intercept locomotive controller 162 will use powergenerated by both APU 50 and engine/generator sets 116. In still othercases, intercept locomotive controller 162 will idle APU 50 and use onlyonboard power produced by engine-generator sets 116.

In one embodiment, the power command transmitted by intercept locomotivecontroller 162 will specify a desired amount of power. In otherembodiments, the power command transmitted by intercept locomotivecontroller 162 may specify a desired operating point on a performancegraph of APU 50 or a desired power level of the output power of APU 50.

In an optimization to this algorithm, railroads may purchase bulk powerfrom power providers using APU 50 as described above. Their powerpurchases may be stored within and reported by a meter (not shown)provided within in APU 50. Intercept locomotive controller 162 mayinterrogate the meter and determine the amount of power remaining in thecurrent bulk purchase, and make its power allocation decisions based atleast in part upon the amount of power previously purchased. This isespecially advantageous when the bulk purchases are “use or lose”, andit is advantageous to the locomotive operator to use all of theirpreviously purchased power. Depending upon the embodiment, theoptimization algorithm can also include the aspect that with APU 50operating, the overall power available to the traction bus 124 can behigher than with the locomotive(s) alone, and there may be portions ofthe route where the higher power has value to the railroad and thereforeit is beneficial for the system to reserve sufficient fuel for thoseportions of the route. As such, the algorithm is looking at several timeperiods to optimize the value of APU operation, not simply as theminimum cost of power now.

Once operational conditions are processed, intercept locomotivecontroller 162 checks for messages from APUs 50 or fuel assemblies 52that have not been processed. These messages are processed, and storedinformation (e.g., ID information, operational information, etc.) aboutthe power sources and/or fuel assemblies are updated periodically. Thesemessages may indicate a change in a removably connected power source 50and/or fuel assembly 52, fuel state or type, the amount of powerprovided by an auxiliary power source, a cost of power provided, anupdated graph, or other change that intercept locomotive controller 162takes into account when optimizing the performance of locomotive consist110.

If power, fuel, or cost information is updated, intercept locomotivecontroller 162 then conducts a series of interactions with the powersources and fuel assemblies to update its stored information to currentvalues. Intercept locomotive controller 162 then recalculates anyinformation it has stored based upon the updated stored values.

After completing the update of the stored information, interceptlocomotive controller 162 determines information that will be used tosupport the power allocation process. This information includes thereal-time amount of power desired by the locomotive (based upon throttlenotch settings, auxiliary loads, traction motor requirements, etc.), anddetermines the current amount of power available by totaling the amountof power each power source may provide. It further determines the powercost for each power source, either as a scalar metric or as anefficiency graph that describes the power costs relative to the amountof power provided, or as a metric or efficiency graph based upon thefuel type/composition. In some cases, fuel cost, operational metricssuch as temperature or air pressure, and other metrics are used asinputs in determining the power cost. Other parameters such as powersources requested to produce a minimum amount of power are alsocollected. In an embodiment, this information may include emissions andor maintenance schedule information about each of the power sources.

Intercept locomotive controller 162 then checks to determine if thepower provided to locomotive 112 is within a configuration specifiedtolerance of the power requested to operate the locomotive 112. If thepower requested and power provided are out of tolerance, or one of thepower cost parameters changed, intercept locomotive controller 162 makesa power allocation between the power sources, dividing the locomotivepower requirement between available power sources, such as, for example,locomotive engine-generator sets 116 and auxiliary power sources such asAPU 50. In one embodiment, the power allocation is performed in a way tominimize the total cost of power utilized by the locomotive 112, usingthe power cost and minimum/maximum amounts of power produced for eachpower source as input. In some embodiments, the power cost is a graphthat represents the varying power cost based upon the amount of powerprovided. Intercept locomotive controller 162 finds the minimum totalcost based upon the amount of power requested, and sets the primarypower sources (e.g., sets excitement and RPMs of generator 120) andsends requests to APUs 50 to provide the desired amount of power.

Power allocation algorithms may be very complex, and may include currentlocation, anticipated power requirements, and other factors in theallocation algorithm. In some embodiments, the power allocation may besimplified to use fuel costs as the allocation factor. For example, whenthe difference between diesel and natural gas fuel prices exceed acertain level, the lower priced fuel is always less expensive tooperate. Similarly, if specific fuels are available, it may moreefficient to operate with those fuels. The results of the powerallocation process are stored in intercept locomotive controller memory146 for subsequent use.

Intercept locomotive controller 162, having configured locomotiveconsist 110 to operate with a specific source and amounts of power thenmonitors the power provided by each power source to determine if theamount of power being provided is in accordance with the settings, andmakes adjustments to the power source configurations as needed to keepthe amount of power provided to the locomotive in line with the powerrequirements. The control loop then repeats on a periodic interval.

In applications where fuel assemblies 52 have direct control and fuelconnections 148, 150 with locomotive 112, valves (not shown) fluidlyconnect pressure tanks 60 to locomotive engines 118. Interceptlocomotive controller 162 may interrogate each fuel assembly 52,determine the type of fuel, its cost, and its energy density, anddetermine which of the available fuels it should use in the currentsituation based on the information received from fuel assemblies 52.After selecting the fuel to use, intercept locomotive controller 162 canconfigure the engine operating parameters (idle, timing, etc.) soengines 78 process the selected fuel most efficiently. For example, itmay be cost effective to use syngas or process gas while engines 78 areidling, and to use LPG when the engines 78 are running at maximum RPM.Similarly, intercept locomotive controller 162 can use fuel cost and/orfuel energy density as inputs in determining which fuel should be usedin the current situation.

In an embodiment that blends power from an APU 50 and the locomotiveengine 118, the amount of power delivered to the traction motors 128 isthe sum of the APU power and the locomotive diesel power. In someinstances, the APU sourced power will comprise the large majority ofpower delivered to the traction motors 128. The challenge is to providesufficient traction motor cooling air when the locomotive 112 is nowgenerally putting out considerably less tractive bus electrical power.For example, while the locomotive engine 118 is no longer operated athigh RPM for the purpose of producing tractive power, lowering the RPMof engine 118 may reduce the amount cooling air provide to the tractionmotors to a level below that appropriate for the level of power flowingon the traction bus 124. As previously described, each of the extantdrive methods depends either directly (mechanical drive, first electricdrive method) or indirectly (second electric drive method in itsavailable power limitations) on the diesel RPM to provide adequatecooling airflow from traction motor blowers 204 to the traction motors128. An example operating plan for intercept locomotive controller 162that maintains the RPM of engine-generator set 116 is detailed above inTABLE 1.

Described herein are various approaches to providing adequate tractionmotor cooling when a legacy locomotive 112 is operating with an APU 50.In a fast idle embodiment (exemplified above by operating plan in TABLE2), the existing traction motor blowers 204 are used and the interceptlocomotive controller 162 transmits a blower motor command that permitslocomotive diesel engine 118 to run at the specific RPM associated witheach notch, but can run with a lower load and therefore lower fuelconsumption and emissions. Note the load on the diesel engine 118 can bemodulated by controlling the excitation of the main and/or companionalternator 120 of the locomotive 112.

The traction motor blowers 204 may be controlled using an electric drivefrom the existing locomotive power train, a mechanical drive fromexisting locomotive power train (i.e., power take off from the dieselengine 118), or a hydraulic drive of the traction motor blowers 204,effected by power take off from the diesel engine 118 to drive ahydraulic pump, connected hydraulically to hydraulic motor drivingtraction motor blower 204, with appropriate valves, accumulators, andpressure regulators in hydraulic lines.

In electric drive embodiments, control of the traction motor blowers 204may be effected via AC directly from the main generator, AC directlyfrom an companion alternator, AC directly from an auxiliary generator,or a combination thereof with added VFD. Alternatively, control may beeffected by inverting DC power from the power bus 124 to drive tractionmotor blowers 204, or driving AC or DC traction motor blowers 204 usingelectric energy stored in batteries on the locomotive 112 or a tender.

In mechanical drive embodiments where the legacy locomotive 112 includesa mechanical drive for the traction motor blowers 204, the mechanicaldrive may be left as is, or a gearbox or transmission may beincorporated to provide either a fixed ratio speed increase or variablespeed for operation of traction motor blowers 204. Alternatively or inaddition thereto, a clutch may be included in the mechanical drive trainof fraction motor blowers 204 to permit complete/rapid periodic/partialdepowering of traction motor blowers 204 when, for example, “fixed”engagement of power train would provide for an excess of blower airaccording to the momentary cooling appropriate for the traction motors128.

In alternative embodiments, the existing traction motor blowers 204 maybe used at a slow diesel RPM/no fast idle condition. In suchembodiments, the locomotive diesel RPM and power output is controlled toproduce enough power, when summed with the power produced by one or morepower sources on one or more auxiliary power unit assemblies 48, to beadequate to supply the amount of power associated with the specificnotch requested by the train crew, including service of locomotive hotelloads including traction motor blowers. In such embodiments, tractionmotor blowers 204 may be controlled using an electric drive from theexisting locomotive power train, a mechanical drive from existinglocomotive power train (i.e., power take off from diesel), or ahydraulic drive of the traction motor blowers, in a similar manner asdescribed above.

In yet another embodiment, a new source of power may be provided fortraction motor blowers 204 such as, for example, an engine smaller thanthe primary engine 118, a fuel cell, or a battery bank. Alternatively,the new source of power may include, for example, a new “auxiliary”prime mover, an electric drive if new auxiliary is a genset or fuelcell, including all AC or DC variants of driving traction motor blowers,a mechanical drive from new auxiliary prime mover shaft power, a batterybank, and transfer of AC or DC power from an APU 50 not on thelocomotive chassis. The sole or shared purpose of this new power sourcewould be to power traction motor blowers 204.

New traction motor blowers may also be provided. Such traction motorblowers may either supplement existing fraction motor blowers andpneumatically connect in parallel or series with extant traction motorblowers, or replace existing traction motor blowers with new ones sizedto yield adequate airflow at low locomotive diesel RPM, either with“excess” airflow at higher RPM or with modulated flow to reduce “excess”airflow at higher RPM.

A refrigeration system may also be included to provide pre-cooled airsupply to cool traction motors 128, thus providing adequate coolingunder either “fast idle” air flow regimes or “slow/no fast-idle” airflow regimes.

An air storage system may also be provided on locomotive 112 for purposeof accumulating compressed air volumes to be released as supplement toe.g., “slow/no fast idle” traction motor blower air flow. A reservoirfor such system could be integral to locomotive chassis or on separatecar chassis. The reservoir could be “pre-charged” before train startstrip and/or replenished by compressor mechanism during train operations.

FIG. 5 illustrates an exemplary control process 220 implemented by anintercept locomotive controller, such as intercept locomotive controller162 described with respect to FIGS. 2-4. This control process 220 may beperformed asynchronously when a control input changes, or upon aregularly scheduled, or calculated, repeating basis. At step 222, theintercept locomotive controller 162 receives control and sensor inputsfrom one or more of the legacy locomotive controller 114,engine/generator sensors 122, power sensors 140, and other sensors 200provided within locomotive 112. The intercept locomotive controller 162transforms these control and sensor inputs into digital values, whichare stored in a memory 164 of the intercept locomotive controller 162.

The intercept locomotive controller 162 then proceeds to step 224wherein a power allocation between available power sources isdetermined. Using the digital values stored in the memory 146 ofintercept locomotive controller 162 during step 222, the interceptlocomotive controller 162 then looks up the resulting power and sensorvalues in one or more power allocation/sensor value lookup tables and/orother control allocation tables. The power and sensor values are storedin memory 164 for use by subsequent steps.

In optional step 226 (shown in phantom), the intercept locomotivecontroller 162 uses at least one of the values stored in memory 164 toprovide a control output to APU 50 in order to set the amount and/orcharacteristics of power provided by the APU 50. In someimplementations, this step may be omitted because the APU 50 providesconsistent power.

In step 228, the intercept locomotive controller 162 then uses at leastone of the values stored in memory 164 to provide a control output tothe engine/generator set 116 of locomotive 112 in order to set theamount and/or characteristics of power provided by the engine/generatorset 116. The process proceeds to step 230, where the interceptlocomotive controller 162 then uses at least one of the values stored inmemory 164 to provide sensor data to the legacy locomotive controller162.

One of the aspects of the intercept locomotive controller 162 is that itpermits the allocation of required power on the traction bus 124 to oneor more locomotive engine/generator sets 116 and/or external power unitsor APUs 50, without changing the existing legacy locomotive controlsystem and engine/generator configuration. This permits the existinglegacy locomotive 112 to operate within its existing emissionscertifications.

A second aspect of the intercept locomotive controller 162 is that itpermits the allocation of requested locomotive power based upon theavailability of lower cost power. In a simple implementation, theallocation may be predetermined and encoded within the memory 164 of theintercept locomotive controller 162. For example, if the external powerunit or APU 50 has a cost per unit power that is significantly below thecost of running the legacy locomotive engine/generator set 116, theintercept locomotive controller 162 may make a power allocation decisionto allocate a majority of the power demand to the APU(s) 50. Thisallocation may range from 50% to 100%, depending upon the relative costof power and restrictions to keep the legacy locomotive engine/generatorset 116 operating in order to provide auxiliary power or for regulatoryreasons. Should regulatory restrictions permit or require a differentallocation range, the intercept locomotive controller 162 can bere-configured to allocate power requests accordingly.

A third aspect of the intercept locomotive controller 162 is that itpermits operation with external, auxiliary power units over which thereis no effective control. When this situation occurs, the interceptlocomotive controller 162 has received inputs from the legacy locomotivecontroller 114 and from a sensor monitoring the power available on thetraction bus 124 or of the draw of one or more traction motors 128.Based upon the amount of power available and/or the power used and theencoded locomotive power setting command inputs from the legacylocomotive controller 114, the intercept locomotive controller 162determines at least one control setting for the legacy locomotiveengine/generator 118, 120 and creates a control signal effective tocontrol the production of tractive power by the legacy locomotiveengine/generator set 116.

A fourth aspect of the intercept locomotive controller 162 is that itpermits legacy locomotives to operate in conjunction with alternativefuel-based power, such as gaseous fuels, without modifying the existinglegacy locomotive controller. Use of such fuels can require additionalmodifications to a legacy locomotive or the use of APUs 50 capable ofusing such fuels. Embodiments of the described systems and methods alsosupport the concept of power arbitrage between differently fueledlocomotive power sources, where the arbitrage is made based upon cost offuel or the cost of delivered power vs. the power requests of locomotivetraction and auxiliary loads.

A fifth aspect of the intercept locomotive controller 162 is that itsupports the use of auxiliary power unit assembly arrangements in orderto permit the provision of additional power to a locomotive over theamount of power that can be produced by the engine/generatorcombination(s) that are part of the diesel locomotive. In someoperational situations, such as when the locomotive consist is runningat higher speeds, the pulling capacity of the locomotive is limited bythe amount of power that can be provided by the locomotives to theirtraction motors. The use of auxiliary power permits the locomotive tomove the train to greater speeds.

Still further, embodiments of the described systems and methods enable ametering-based power delivery approach, where the locomotive power usefrom alternative fuel power sources is metered and may be separatelyinvoiced or billed to the railroad or locomotive operator. While thesystems and methods of use set forth herein are described as being usedin connection with the locomotive industry, one skilled in the art willrecognize that the benefits of the fuel assembly, rail car assembly, andmethod for providing fuel are equally applicable to any number ofalternative industrial applications in which a fuel tank is coupled toan engine, such as, for example, in the trucking industry or themaritime industry.

One key aspect when using alternative fuel types in an auxiliary powerunit assembly is the differential in fuel cost, or ultimately, the costof a unit of power provided to a power bus. Embodiments of the interceptlocomotive controller 162 set forth herein are able to arbitrage fueland power costs between the locomotive's power sources and auxiliarypower unit assemblies provided in a power tender to more efficientlyoperate. Further, the intercept locomotive controllers and auxiliarypower unit assemblies set forth herein are able to communicateadditional information (such as its ID, control input description,control settings/emissions, control setting/generated power graphs, fueltype, power cost) about the control and operation of the auxiliary powerunit to the intercept locomotive controller 162. Absent at least some ofthis information, the intercept locomotive controller 162 would beunable to effectively control the auxiliary power units.

Various features and aspects of the above described system may be usedindividually or jointly. Further, although embodiments of the interceptlocomotive controller have been described in the context of itsimplementation in a particular environment, and for particularapplications (e.g., railroad usage), those skilled in the art willrecognize that its usefulness is not limited thereto and that the systemcan be beneficially utilized in any number of environments andimplementations where it is desirable to retrofit existing powergenerator controllers in order to use external power units or toarbitrage power costs from alternative fuel generation sources.

More generally, from the foregoing, it will be appreciated that specificembodiments of the technology have been described herein for purposes ofillustration, but that various modifications may be made withoutdeviating from the technology. Certain aspects of the technologydescribed in the context of particular embodiments may be combined oreliminated in other embodiments. Further, while advantages associatedwith certain embodiments of the technology have been described in thecontext of those embodiments, other embodiments may also exhibit suchadvantages, and not all embodiments need necessarily exhibit suchadvantages to fall within the scope of the present technology.Accordingly, the disclosure and associated technology can encompassother embodiments not expressly shown or described herein.

A technical contribution for the disclosed method and apparatus is thatit provides for a computer implemented control an intercept locomotivecontroller that programmed to receive a control signal indicating anrequested amount of locomotive power from the legacy locomotivecontroller, allocate a portion of the requested amount of locomotivepower to an auxiliary power unit, and control the auxiliary power unitto deliver the portion of the amount of locomotive power to the powerbus.

One skilled in the art will appreciate that embodiments of the inventionmay be interfaced to and controlled by a computer readable storagemedium having stored thereon a computer program. The computer readablestorage medium includes a plurality of components such as one or more ofelectronic components, hardware components, and/or computer softwarecomponents. These components may include one or more computer readablestorage media that generally stores instructions such as software,firmware and/or assembly language for performing one or more portions ofone or more implementations or embodiments of a sequence. These computerreadable storage media are generally non-transitory and/or tangible.Examples of such a computer readable storage medium include a recordabledata storage medium of a computer and/or storage device. The computerreadable storage media may employ, for example, one or more of amagnetic, electrical, optical, biological, and/or atomic data storagemedium. Further, such media may take the form of, for example, floppydisks, magnetic tapes, CD-ROMs, DVD-ROMs, hard disk drives, and/orelectronic memory. Other forms of non-transitory and/or tangiblecomputer readable storage media not list may be employed withembodiments of the invention.

A number of such components can be combined or divided in animplementation of a system. Further, such components may include a setand/or series of computer instructions written in or implemented withany of a number of programming languages, as will be appreciated bythose skilled in the art. In addition, other forms of computer readablemedia such as a carrier wave may be employed to embody a computer datasignal representing a sequence of instructions that when executed by oneor more computers causes the one or more computers to perform one ormore portions of one or more implementations or embodiments of asequence.

Therefore, according to one embodiment of the invention, a locomotiveassembly includes a locomotive having a power bus, a primary power unitcoupled to the power bus, and a legacy locomotive controller programmedto transmit control signals to the primary power unit. The locomotiveassembly further includes an intercept locomotive controller programmedto receive a control signal indicating an requested amount of locomotivepower from the legacy locomotive controller, allocate a portion of therequested amount of locomotive power to an auxiliary power unit, andcontrol the auxiliary power unit to deliver the portion of the amount oflocomotive power to the power bus.

According to another embodiment of the invention, a method ofcontrolling a locomotive includes relaying a control signal from alegacy locomotive controller to an intercept locomotive controller, thecontrol signal comprising an encoded request for a locomotive powersetting. The method also includes determining a desired power outputcorresponding to the locomotive power setting and allocating a firstportion of the desired power output to an auxiliary power source.Further, the method includes transmitting an auxiliary command signalfrom the intercept locomotive controller to the auxiliary power sourceto cause the auxiliary power source to supply the first portion of thedesired power output to a locomotive bus on the locomotive.

According to yet another embodiment of the invention, a retrofit kit fora locomotive includes a first control interface electrically coupleableto a legacy locomotive controller on the locomotive. The retrofit kitalso includes an auxiliary power unit assembly having an auxiliary powersource, an auxiliary controller programmed to control the auxiliarypower source, a power cable coupleable to a power bus of the locomotive,and a second control interface electrically coupled to the auxiliarycontroller. Further, the retrofit kit includes an intercept locomotivecontroller electrically coupled to the first and second controlinterfaces. The intercept locomotive controller is programmed tointerpret a signal received on the first control interface as a requestfor locomotive power, define an auxiliary power command based on therequest for locomotive power, and transmit the auxiliary power commandto the auxiliary power unit assembly via the second control interface.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments.

Accordingly, the invention is not to be seen as limited by the foregoingdescription. The patentable scope of the invention is defined by theclaims, and may include other examples that occur to those skilled inthe art. Such other examples are intended to be within the scope of theclaims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal language of theclaims.

What is claimed is:
 1. A locomotive assembly comprising: a locomotivecomprising: a power bus; a primary power unit coupled to the power bus;and a legacy locomotive controller programmed to transmit a controlcommand to the primary power unit; and an intercept locomotivecontroller programmed to: receive a control signal indicating anrequested amount of locomotive power from the legacy locomotivecontroller; allocate a portion of the requested amount of locomotivepower to an auxiliary power unit; and control the auxiliary power unitto deliver the portion of the amount of locomotive power to the powerbus.
 2. The locomotive assembly of claim 1 wherein the interceptlocomotive controller is programmed to receive a control signalindicating a requested alternator excitation from the legacy locomotivecontroller.
 3. The locomotive assembly of claim 2 wherein the controlsignal comprises a pulse generated by a silicon controlled rectifier(SCR).
 4. The locomotive assembly of claim 2 wherein the control signalcomprises a pulse-width-modulated (PWM) signal.
 5. The locomotiveassembly of claim 1 wherein the primary power unit comprises at leastone engine/generator set.
 6. The locomotive assembly of claim 1 whereinthe auxiliary power unit comprises: an auxiliary power source coupled tothe power bus; and an auxiliary controller electrically coupled to theauxiliary power source.
 7. The locomotive assembly of claim 6 whereinthe intercept locomotive controller is further programmed to: transmit acontrol command to the auxiliary controller to deliver the portion ofthe amount of locomotive power to the power bus; and receive sensorsignals from at least one sensor provided on the auxiliary power unit.8. The locomotive assembly of claim 1 further comprising: a first sensorcoupled to the power bus; and wherein the intercept locomotivecontroller is further programmed to: intercept a sensor signaltransmitted from the first sensor to the legacy locomotive controller;modify the sensor signal; and transmit the modified sensor signal to thelegacy locomotive controller.
 9. The locomotive assembly of claim 8wherein the intercept locomotive controller is further programmed tomodify the sensor signal in accordance with the original powerrequested.
 10. The locomotive assembly of claim 1 further comprising: asecond sensor coupled to the primary power unit; and wherein theintercept locomotive controller is further programmed to: intercept asensor signal transmitted from the second sensor to the legacylocomotive controller; modify the sensor signal; and transmit themodified sensor signal to the legacy locomotive controller.
 11. Thelocomotive assembly of claim 1 further comprising: a traction motorelectrically coupled to the primary power unit; and a traction blowerpositioned adjacent the traction motor; and wherein the interceptlocomotive controller is further programmed to: intercept a tractionblower command signal transmitted from the locomotive controller to thetraction blower; modify the traction blower command signal; and transmitthe modified fraction blower command signal to the traction blower. 12.The locomotive assembly of claim 11 wherein the intercept locomotivecontroller is further programmed to modify the traction blower commandsignal to match a traction blower command signal corresponding to therequested amount of locomotive power.
 13. A method of controlling alocomotive comprising: relaying a control signal from a legacylocomotive controller to an intercept locomotive controller, the controlsignal comprising an encoded request for a locomotive power setting;determining a desired power output corresponding to the locomotive powersetting; allocating a first portion of the desired power output to anauxiliary power source; and transmitting an auxiliary command signalfrom the intercept locomotive controller to the auxiliary power sourceto cause the auxiliary power source to supply the first portion of thedesired power output to a locomotive bus on the locomotive.
 14. Themethod of claim 13 further comprising: allocating a second portion ofthe desired power output to a legacy engine/generator set coupled to thelegacy locomotive controller; generating a synthesized control signalcomprising an encoded request for a locomotive power settingcorresponding the second portion of the desired power output; andtransmitting the synthesized control signal from the interceptlocomotive controller to the legacy locomotive controller to cause thelegacy engine/generator set to supply the second portion of the desiredpower output to the locomotive bus.
 15. The method claim 14 furthercomprising: intercepting a sensor signal transmitted from a power sensorcoupled to the legacy engine/generator set to the legacy locomotivecontroller; generating a synthesized sensor signal representative of thelegacy engine/generator set operating to produce the desired poweroutput; and transmitting the synthesized sensor signal from theintercept locomotive controller to the legacy locomotive controller tothe to the legacy locomotive controller.
 16. The method claim of claim14 further comprising: intercepting an initial blower motor settingtransmitted from the legacy locomotive controller to a traction blowermotor of the locomotive; determining a modified traction blower motorsetting based on the desired power output; and transmitting the modifiedblower motor setting from the intercept locomotive controller to thetraction blower motor.
 17. A retrofit kit for a locomotive comprising: afirst control interface electrically coupleable to a legacy locomotivecontroller on the locomotive; an auxiliary power unit assemblycomprising: an auxiliary power source; an auxiliary controllerprogrammed to control the auxiliary power source; a power cablecoupleable to a power bus of the locomotive; and a second controlinterface electrically coupled to the auxiliary controller; and anintercept locomotive controller electrically coupled to the first andsecond control interfaces, wherein the intercept locomotive controlleris programmed to: interpret a signal received on the first controlinterface as a request for locomotive power; define an auxiliary powercommand based on the request for locomotive power; and transmit theauxiliary power command to the auxiliary power unit assembly via thesecond control interface.
 18. The retrofit kit of claim 17 wherein theintercept locomotive controller is further programmed to: define alocomotive power command based on the request for locomotive power; andtransmit the locomotive power command to a primary power source coupledto the legacy locomotive controller; and wherein the locomotive powercommand causes the primary power source to produce less than a totalamount of power associated with the request for locomotive power. 19.The retrofit kit of claim 18 wherein the intercept locomotive controlleris further programmed to: identify an operating cost of the auxiliarypower source; identify an operating cost of the primary power source;and define the auxiliary power command and the locomotive power commandto minimize a total cost of providing power consistent with the requestfor locomotive power.
 20. The retrofit kit of claim 17 furthercomprising: a first sensor interface electrically coupleable to thelegacy locomotive controller; and a second sensor interface electricallycoupleable to at least one locomotive sensor; and wherein the interceptlocomotive controller is electrically coupled to the first and secondsensor interfaces; and wherein the intercept locomotive controller isfurther programmed to: intercept a sensor signal transmitted from the atleast one locomotive sensor via the second sensor interface; modify thesensor signal to reflect an expected sensor signal based on the requestfor locomotive power; and transmit the modified sensor signal to thelegacy locomotive controller via the first sensor interface.
 21. Theretrofit kit of claim 20 wherein the intercept locomotive controller isfurther programmed to modify the sensor signal using data stored in alookup table.
 22. The retrofit kit of claim 20 wherein the interceptlocomotive controller further comprises a memory; and wherein theintercept locomotive controller is further programmed to: transform thesensor signal into a digital value; and store the digital value in thememory.
 23. The retrofit kit of claim 17 wherein the interceptlocomotive controller is further programmed to: intercept a blower motorcommand transmitted by the legacy locomotive controller; generate amodified blower motor command; and transmit the modified blower motorcommand to a blower motor of the locomotive.
 24. The retrofit kit ofclaim 17 wherein the intercept locomotive controller is furtherprogrammed to: intercept a traction motor command transmitted by thelegacy locomotive controller; generate a modified traction motorcommand; and transmit the modified traction motor command to a tractionmotor of the locomotive.